nptl: x86_64: Use same code for CURRENT_STACK_FRAME and stackinfo_get_sp

Cherry-picked by scw@google.com from 8cd559cf5afe3894f92c2be6f972e1a4e38c56ca
with local modifications (different file path and not use macros introduced in
01bd62517cc242ae503aaa7002e9e94551803e4d). This fixes UB and code
removal when building with clang.

It avoids the possible warning of uninitialized 'frame' variable when
building with clang:

  ../sysdeps/nptl/jmp-unwind.c:27:42: error: variable 'frame' is
  uninitialized when used here [-Werror,-Wuninitialized]
    __pthread_cleanup_upto (env->__jmpbuf, CURRENT_STACK_FRAME);

The resulting code is similar to CURRENT_STACK_FRAME.

Checked on x86_64-linux-gnu.

diff --git a/sysdeps/x86_64/nptl/pthreaddef.h b/sysdeps/x86_64/nptl/pthreaddef.h
index 036deb577238b652bdbae9dfb93fd1e160d132e9..7cf6677114aebe45c907ada51f8d5ecd4b50e281 100644 (file)
--- a/sysdeps/x86_64/nptl/pthreaddef.h
+++ b/sysdeps/x86_64/nptl/pthreaddef.h
@@ -41,4 +41,6 @@
 
 /* Location of current stack frame.  The frame pointer is not usable.  */
 #define CURRENT_STACK_FRAME \
-  ({ register char *frame __asm__("rsp"); frame; })
+  ({ register void * p__ __asm__("rsp"); \
+     asm volatile("" : "=r" (p__)); \
+     p__; })

diff --git a/sysdeps/x86_64/stackinfo.h b/sysdeps/x86_64/stackinfo.h
index f7a5672f275cd5edd58c4c030f1a10dd54cfdee1..1301c5e197d134571093051679e93235a5299c26 100644 (file)
--- a/sysdeps/x86_64/stackinfo.h
+++ b/sysdeps/x86_64/stackinfo.h
@@ -34,7 +34,9 @@
    for which they need to act as barriers as well, hence the additional
    (unnecessary) parameters.  */
 #define stackinfo_get_sp() \
-  ({ void *p__; asm volatile ("mov %%" RSP_LP ", %0" : "=r" (p__)); p__; })
+  ({ register void * p__ __asm__(RSP_LP); \
+     asm volatile("" : "=r" (p__)); \
+     p__; })
 #define stackinfo_sub_sp(ptr) \
   ({ ptrdiff_t d__;                                            \
      asm volatile ("sub %%" RSP_LP " , %0" : "=r" (d__) : "0" (ptr));  \